Appaeatus



(No Model.)

Gr. KAPPENBERGER.

V DIGESTING APPARATUS.

No. 448,581. Patented Mar. 17,1891.

N W K fi w Witnesses Inventor WJJ MW v UNITED STATES PATENT Orrrcnt GUSTAV KAFFENBERGER, OF CLEVELAND, OHIO, ASSIGNOR OF ON E-FOURTH TO ARNOLD .DOLL, OF SAME PLACE.

DIGESTING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 448,581, dated March 17, 1891.

Application filed November 19, 1890. Serial No. 371,969. (No model.) i

To a whom it may concern.-

Be it known that I, GUSTAV KAFFENBER- GER, of Cleveland, Ouyahoga county, Ohio, have invented certain new and useful Improvements in Digesting Apparatus, of which the following is a specification.

XVhcre material is to be subjected to a process of digestion or cooking or diffusion, the general process usually employed may be 1 briefly described as consisting in putting the material into a vessel along with the liquor of treatment, and when the materialhas been subjected to the action of the liquor for a sufficient length of time emptying the vessel and then proceeding with a new charge, the liquor being probably withdrawn or weakened or strengthened during the operation. In some cases the operation will consist of asuccession of steps-say in different vesselswhereby the material is subjected to the action, progressively, in the operation of stronger liquor or liquor having superior capacity for action, the general principle being that weak liquor can best attack the fresh 5 raw material, while stronger liquor must be employed upon the more resisting poorer material.

The object of the present invention is to produce a digesting apparatus in which the process may be carried on in a practically continuous manner, the raw material going into one end of the apparatus and coming out at the other end in a substantially-continuous stream of progression.

The improvement will be readily understood from the following description, taken in connection with the accompanying drawing, which is a vertical section of a digesting apparatus exemplifying myinvention. In the general description which follows I will as sume, as a mere example, that the material to be operated upon is straw to be digested for paper-making purposes, other uses of the system for purposes of digesting, cooking, or

- diffusion being then self-explaining.

In the drawing, A indicates a long pipe, whose course of direction may be as desired vertical, horizontal, spiral, or what not; B, the receiving end of the pipe, shown as provided with a hopper for the reception of the straw to be treated; O, a valve at the receiving end of the pipe atthe foot of the hopper;

D, a valve in the pipe near the receiving end after the valve O; E, a valve in the pipe after the valve D and near that valve; F, the terminal or discharge end of the pipe; G, a valve in the pipe near the discharge end; II, a valve in the pipe near the valve G and before that valve; J, that portion of the pipe comprehended between the valves E and II, this portion of the pipe constituting the digestingchamber; K, a chamber formed by that portion of the pipe between valves D and E; L,

a chamber formed by that portion of the pipe between the valves G and H; M, a piston 'work- 6 ing in a cylinder whose end is open to chamber K; N, a piston working in a cylinder whose end is open to chamber L; O, a ventpipe communicating with chamber K through perforations which will permit the escape of 0 vapors, but not of straw, from chamber K; P, a valve in the vent-pipe; Q, a rotary cam-shaft exemplifying means for operating the valves and pistons in proper order; R, a rotary draining-bushing in the pipe just after the valve E; S, spiral vanes projecting inwardly from this draining -bushing, whereby the rotary drainer becomes a conveyer, which will tend to urge forward upon the mass of material within the digesting-chamber; T, a heater; U, a pump to draw liquor from the drainer through the heater and discharge it into the digesting-chamber J, further along in the length of the digesting-chambcrsay near its terminal at the valve H; 8 V, the liquor-pipe conveying the liquor from the drainer through the heater and pump again to the digesting-chamber; W, a pipe to supply fresh liquor in addition to the liquor which is withdrawn from the drainer; X, a 0- pipe to supply steam to the heater; Y, a pipe for the discharge of water for condensation from the heater; Z, a pipe to admit liquor to the material at the receiving end of the apparatus, this pipe being preferably connected to a pump which takes its supply from liquor drained from material which has been discharged from the apparatus, whereby such greatly-exhausted liquor as to heat or strength becomes used in the treatment of the richest 10o straw; a, aleverconnect'ing the stem of valves E and H with the stem of valve 0; b, a lever I V V V V V l on the stem of valve P; c, a tappet on the stem of valve E, adapted, when valve E has closed, to open vent-valve P; d, the connected stems of valves E and II; c, the connected stems of valves D and G; f, cams on the camshaft Q for operating the valves and pistons, the two pistons being also united by a common piston-rod; g, a worm to be continuously rotated, engaging a worm-wheel on the drainbushing R.

I have shown exemplifying mechanism for giving motion in proper time to all the valves and pistons. The character of this mechanism is entirely immaterial to myinvention so long as it will give the proper motion to the parts, and, indeed, it is not even necessary that there be any such uniting mechanism, as the separate valves and pistons may be independently moved in proper order.

It will be noticed that the digesting-chamber J, when the valves are in the position shown, extends from valve D to valve G. The digesting chamber throughout this entire length represents a large clear conduit to contain and pass the material to be operated upon-say straw. Assume this entire digesting-chamber to be full of straw and charged with hot cooking-liquor. Assume, further, that the cooking temperature is such as to maintain comparatively high pressure in the digesting-chainber. The walls of the apparatus must be strong enough to resist this pressure. The rotation of the drain-bushing R tends to urge this mass forward in the digester. Liquor which drains from the drainbushing It goes through the heater and becomes reheated and is pumped into the mass farther on in the digester, fresh liquor being charged at \V if needed to keep up the strength of the liquor. In this way the mass in the digesting-chamber is being subjected to the action of liquor moving through it in a direction backward through the digester, and the mass of material has a tendency, by reason of the conveyer-vanes S, to move forward in the digesteiyif such movement is possible. Material near the initial end of the digester may be quite rich fresh material which has been acted upon but a short time, while material near the terminal end may be said to be loan or thoroughly-digested material which has been a long time acted upon, having passed through the length of the digester. The liquor circulated by the pump U and reheated and strengthened is thus moving through the mass of material from lean material to richer material. The liquor as it proceeds through the mass becom es, of course, more exhausted in strength or heat, but comes into action on material of increasing richness, and consequently of less resistance to the liquor.

it will be noticed that piston N is up, the material in the digester thus occupying also the cylinder-space under this piston. The material in the chamber L is digested mateterial, as thoroughly digested as the apparatus is capable of, that material having passed through the length of the digesting-chamber. Chamber K is also full of material of the freshest character which is confined within the apparatus. Assume fresh dry straw to be in the hopper B, into which it may be delivered by any suitable form of carrier, the delivery being, if desired, continuous. Now let valves E and H be closed, and then let vent-valveP be opened. This cuts off the two chambers K and L from the balance of the digesterchamber, and the pressure in chamber K relieves itself through the vent-pipe. Now let valves D and G be opened and let both pistons move down. The downward movement of piston N, in conjunction with the pressure in chamber L, has discharged some of the contents of chamber L through open valve G and out of the digester. At the same time the descent of piston M has enlarged the capacity of chamber K. Valve 0 is to have been opened, and consequently straw from the hopper and between the hopper and valve 1) will pass into chamber K to take possession of the additional holding capacity resulting from the descent of piston M. The new straw then passing into chamber K is charged with liquor pumped in through pipe Z, and this liquor may, as before stated, be weak liquor drained from material discharged from the digester, this weak liquor having to deal immediately only with fresh, rich, lo w-resistance straw. Now let valves 1) and G close and valve C also. Then let the vent-valve P be closed. Then let valves E and ll be opened.

Chambers K and L have now become again portions of the common digesting-chamber. Now let pistons M and N rise. Theirmotion will make more room in chamber L and less room in chamber K, and the mass will thus be forced forward in the digester from the point where piston M is compressing to the point where piston N has provided additional room. The mass is also being constantly urged forward in the digester by the conveyer-vanes S. The valve and piston motions are continuous repeated in the manner indicated, and consequently the straw will be moving constantly forward through the digester and passing out at F in a practically constant stream. Thelength of the digesterconduit should be such that the material in passing through it occupies at least that length of time which is requisite to the proper digestion of the material.

With some kinds of material and with some lengths of conduit there will be no need for the vanes S or any equivalent conveyer in the conduit, the action ofthe valves and pistons being sufficient to move the material forward, and. again in other cases the conveyor S would not only be needed, but it may be insufficient, and more similar or equivalent conveyers may need to be distributed along the length of the conduit to urge the material through the digester.

The liquor-circulatiug system illustrated is preferable in dealing with some materials, but not in all cases. In some cases it will be sufficient if the injection at Z be depended on and in other cases an injection through W. This injected liquid going into the digesterchamber at any desired point or' points may be found preferable Without circulation of liquid-that is to say, without withdrawal and circulation of the same liquortheliquor of digestion being simply injected into the mass and carried outwith the digested mass, from which it may be subsequently drained.

It is to be understood, of course, that the digested material passing from the outlet 1? is to be subjected to any further treatment, as draining, Washing, grinding, &c., that may be called for. I

It will be observed that the main principle of my improved digester rests in the fact that the digester consists of three chambers A, K, and L, the latter two forming, alternately, connected portions of chamber A and portions entirely out off from chamber A, the pistons M and N serving as displacement agents for alternately contracting. and enlarging the holding capacity of chambers K and L. It will be further observed that While it is essential in the system to enlarge chamber K, so as to permit that chamber to receive additional material, it is not essential that chamber L shall be enlarged by means of a piston N or its equivalent. When valve H is closed and valve G opened, then more or less of the contents of chamber L will obviously leave chamber L by gravity and by the outblowiug effect of the pressure in the chamber. Therefore when valve G closes again the chamber L, While its capacity has not been enlarged, will have become partially emptied, so as to be capable, when valve H is opened again, of permitting forward movement of the material in the digester. Therefore While displacing agent N is useful it is not essential.

I claim as my invention- 1. In a digester, the combination, substantially as set forth, of a conduit having a receiving end and a discharge end, two valves near the discharge end of the conduit forming a chamber in the conduit between the valves, a second pair of valves near the receiving end of the conduit forming a chamber in the conduit between them, a cylinder open to the chamber formed by said second pair of valves, a displacing-piston in said cylinder, and a liquor-inlet to said conduit.

2. In a digester, the combination, substantially as set forth, of a conduit, a pair of valves near the receiving end thereof, a second pair of alves near the discharge end thereof, a cylinder at each pair of valves open to the chamber formed between the valves of the pair, a displacing-piston in each cylinder, and a liquor-inlet to the conduit.

3. In a digester, the combination, substantially as set forth, of a conduit, a pair of valves, a cylinder, and a displacing-piston near each end of the conduit, a conveyer in the conduit between the two pairs of valves, and a liquor-inlet to the conduit.

4. In a digester, the combination, substantially as set forth, of a conduit, a pair of valves, a cylinder, and a displacing piston near each end 0f the conduit, a liquor-inlet to and a liquor-outlet from the conduit between the two pairs of valves, and a circulating-pump connected ,Wlllll said inlet and outlet. j

5. In a digester, the combination, substantially as set forth, of a conduit, a pair of valves, a cylinder, and a piston near the receiving end of the conduit, a pair of valves near the discharge end of the conduit, and mechanism connecting and arranged to operate the valves and piston.

GUSTAV KAFFENBERGER.

Witnesses:

ARNOLD DoLL, J r., JAMES W. WALKER. 

